1 /* $OpenBSD: ohash_lookup_memory.c,v 1.3 2006/01/16 15:52:25 espie Exp $ */ 2 /* ex:ts=8 sw=4: 3 */ 4 5 /* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include "ohash_int.h" 21 22 unsigned int 23 ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv) 24 { 25 unsigned int i, incr; 26 unsigned int empty; 27 28 #ifdef STATS_HASH 29 STAT_HASH_LOOKUP++; 30 #endif 31 empty = NONE; 32 i = hv % h->size; 33 incr = ((hv % (h->size-2)) & ~1) + 1; 34 while (h->t[i].p != NULL) { 35 #ifdef STATS_HASH 36 STAT_HASH_LENGTH++; 37 #endif 38 if (h->t[i].p == DELETED) { 39 if (empty == NONE) 40 empty = i; 41 } else if (h->t[i].hv == hv && 42 memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) { 43 if (empty != NONE) { 44 h->t[empty].hv = hv; 45 h->t[empty].p = h->t[i].p; 46 h->t[i].p = DELETED; 47 return empty; 48 } else { 49 #ifdef STATS_HASH 50 STAT_HASH_POSITIVE++; 51 #endif 52 } return i; 53 } 54 i += incr; 55 if (i >= h->size) 56 i -= h->size; 57 } 58 59 /* Found an empty position. */ 60 if (empty != NONE) 61 i = empty; 62 h->t[i].hv = hv; 63 return i; 64 } 65